P6/XER schedule review: what to check after import

An XER can import cleanly, populate the activity table, and draw a convincing Gantt chart while still missing the approvals, procurement steps, or logic that control completion. Import success shows that the receiving tool can parse the export. It does not prove the forecast.

A schedule can look busy and still omit the chain that determines when the job finishes.

#The first pass after import, in order

Run these steps in this order: a wrong data date makes every later date misleading, so it comes first. They are a first pass, not the whole review. The numbered questions further down give the reasoning and the sources behind each one.

Step	What to check
Step 1: Data date	Confirm the data date in the file matches the one delivered with it and is consistent with the reporting period. Check that actual dates fall on or before it and remaining work falls after it. Flag it when the data date is missing or differs from the narrative, or an actual start or finish sits after it.
Step 2: Logic, open ends, and relationship types	List activities with no predecessor or no successor. Count relationships by type, then read every start-to-finish relationship and every large lag. Flag it when an open end has no stated reason, a start-to-finish relationship is unexplained, or a lag appears to stand in for work.
Step 3: Calendars	List the calendars in the file and the activities that use each. Compare working days, holidays, shift patterns, and any weather or seasonal calendars with how the work will be done. Flag it when a calendar makes a relationship or duration physically implausible, or nobody can say why it is assigned.
Step 4: Constraints	List every activity that carries a constraint, hard constraints first. Flag it when a constraint forces a date the logic would not produce, or nobody can state its basis.
Step 5: Missing records and activities	Compare the activities with the WBS, the delivery documents, the prior accepted update, and the records behind the actuals. Flag it when an approval-to-delivery chain, a closeout activity, or an activity from the prior accepted update is missing and nothing explains why.
Step 6: Escalate	When any earlier step leaves a question you cannot answer from the file, write one line with the record reference: the file name, the data date, and the activity ID, relationship, or calendar concerned. Escalate to the responsible scheduler or schedule owner with that record reference. Keep the wording a question: a flag is not a conclusion about delay, defect, or breach.

For format questions, such as what an XER contains and what an export leaves out, start with the XER file explainer. This article takes the format as given.

#Begin with the file's identity

Before reviewing float or the longest path, establish what you actually received.

At minimum, record:

• project and contract identifier;
• schedule type: baseline, recovery, update, or what-if;
• file name and source;
• Primavera P6 version or export compatibility;
• data date;
• reporting period;
• baseline assigned for comparison; and
• the narrative, change log, and reports delivered with the file.

UFGS 01 32 01.00 10 separates compatibility from content. For projects using that federal template, it calls for an importable P6/XER file and separately requires the schedule type, contract number, data date, unique file name, narrative, and reports.¹ A receiving tool parsing an export establishes neither field preservation across systems nor the quality of the schedule inside it.

#1. Does the schedule cover the work?

Start with scope before calculating anything.

The U.S. Government Accountability Office's Schedule Assessment Guide organizes ten best practices under four characteristics: comprehensive, well-constructed, credible, and controlled.² Its first point is the most basic and the most easily skipped: capture all activities needed to complete the work, including work performed by both the owner and contractors.

For construction, compare the schedule against the work breakdown structure and the documents that define delivery. Look for:

• design packages and permits;
• owner, utility, and authority approvals;
• critical submittal preparation, review, resubmission, and approval;
• procurement, fabrication, delivery, and inspection;
• access, shutdown, or seasonal work windows;
• testing, adjusting, balancing, and commissioning;
• O&M manuals and as-built drawings;
• pre-final inspection, punch correction, and final inspection.

UFGS 01 32 01.00 10 explicitly calls for many of these activities in the schedule used under that specification. It also defines "long lead" for its template as a procurement sequence over 90 calendar days.¹ That 90-day threshold is not a universal industry definition. Whatever the contract's threshold, every material or assembly capable of controlling the work needs a visible approval-to-delivery chain.

If switchgear installation is in the file but the approved-submittal, release, fabrication, factory testing, delivery, and setting activities—where required or controlling—are not, the schedule may not be modeling the whole path.

#2. Is the logic a real execution plan?

Dates alone do not explain why one activity follows another.

Trace the major work paths and look for:

• activities without predecessors or successors;
• excessive lags standing in for actual work;
• hard constraints that force a desired date;
• start-to-finish relationships that need explanation;
• out-of-sequence progress left unresolved;
• summary activities used as logic anchors; and
• calendars that make the relationship physically implausible.

The federal UFGS template permits only the first and last activities to remain open-ended and requires other activities to carry predecessor and successor logic.¹ A different contract may set a different rule, but open ends remain a useful diagnostic. An unexplained open end can keep a delayed activity from affecting anything downstream.

Read the logic against how the work will be built. A finish-to-start link from "submit shop drawings" directly to "install equipment" is not enough if approval, procurement, fabrication, delivery, and inspection sit between them.

#3. Can you reproduce the critical path and float story?

"Critical" is not a color applied to a bar. It is the result of the schedule's logic, calendars, durations, constraints, and status.

GAO recommends validating the critical path and checking whether total float is reasonable.² In practice, that means asking:

• Does the longest path run through work that could actually control completion?
• Does it terminate at the contractual completion milestone?
• Do major interim milestones have their own driving paths?
• Did a constraint, calendar, or lag create the result?
• Are high-risk near-critical paths visible, or hidden behind an arbitrary float threshold?
• If the path changed this period, does the narrative explain why?

Do not review total float as an isolated ranking. Two activities with the same float can carry very different field, procurement, and contractual consequences. The number needs its logic and source context.

#4. Do durations and calendars match the work?

A five-day activity means nothing until you know which five days count.

Review base calendars, holidays, shift patterns, weather or seasonal calendars, owner-review calendars, and special shutdown windows. Then inspect whether they are assigned to the right activities.

Durations deserve the same scrutiny. Long activities can hide progress. Extremely short activities can create a false sense of precision. GAO's guide calls for realistic activity durations and resource assignments; the appropriate detail should allow progress to be measured without turning the file into noise.²

For unusual durations, constraints, lags, or calendars, ask for the basis. A schedule is easier to govern when assumptions are written down rather than reverse-engineered after the date moves.

#5. Do the actuals agree with the field record?

The data date divides actual history from forecast work.² Treat it as a hard boundary.

Check actual starts, actual finishes, remaining durations, percent complete, and out-of-sequence work against daily reports, approved pay quantities, meeting records, and other accepted project records. Reconcile exceptions; do not automatically overwrite one source with another.

UFGS 01 32 01.00 10 disallows software defaults that automatically assign actual start and finish dates under its federal contract template. It also requires those dates to match the contractor quality-control reports.¹ A date becomes an actual because the work record supports it, not because the scheduling software needed a value.

#6. Does the update explain its changes?

A monthly file should not arrive as an unexplained replacement for last month's file.

Compare the current update with the prior accepted update and baseline. Review:

• added and deleted activities;
• logic changes;
• duration and remaining-duration changes;
• calendar changes;
• lag changes;
• constraints;
• changed actual dates;
• changed longest path; and
• milestone variance.

The UFGS schedule narrative calls for activity-level explanations of these changes and discussion of out-of-sequence work and longest-path movement.¹ GAO similarly treats regular status updates and controlled baseline maintenance as separate best practices.²

Variance is not automatically a problem. Unexplained variance is.

Retain the evidence behind the review: file identity, a scope crosswalk, logic and path reports, the basis for calendar or duration exceptions, records supporting actuals, and the disposition of each change. That trail turns "the schedule looks wrong" into questions someone can verify.

#Where SP4N fits

SP4N can import supported Primavera schedules, including XER or PMXML files. Compatibility varies by customer environment and file. A reviewer can work through flagged schedule questions with the source context alongside them and record the disposition.

The import does not certify the schedule or make it contract-compliant. Learn more about source-linked construction project controls and construction schedule risk review.

#The file opening is the start of the review

A reliable schedule is a controlled model of the work, the handoffs, the current status, and the assumptions behind the forecast. P6 rendering shows that the file is readable; confidence comes from tracing the forecast through its logic and back to the project record.

Have one schedule update and the records behind it? Talk with us about a scoped pilot.

Frequently asked

What does a successful XER import actually prove?

It means the receiving tool was able to parse the export and populate its activity table and Gantt chart. It does not mean the schedule is complete, that its logic is sound, or that the forecast is trustworthy—import success only shows compatibility, not content.

What is the first thing to check before reviewing float or the critical path?

Establish the file's identity: the project and contract identifier, schedule type, file name and source, P6 version, data date, reporting period, the baseline it compares against, and the narrative, change log, and reports delivered with it.

How should total float be reviewed on a P6 schedule?

Total float should not be read as an isolated ranking. Validate that the critical path runs through work that could actually control completion, terminates at the contractual milestone, and that any change in the path this period is explained in the narrative.

What should a monthly schedule update explain?

A schedule update should account for added and deleted activities, logic changes, duration and remaining-duration changes, calendar and lag changes, constraints, changed actual dates, a changed longest path, and milestone variance—unexplained variance is the problem, not variance itself.

Sources

1. 1UFGS 01 32 01.00 10 — Project ScheduleU.S. Army Corps of Engineers · August 2026See sections 2.1, 3.3, 3.4, and 3.5.
2. 2GAO-16-89G — Schedule Assessment Guide: Best Practices for Project SchedulesU.S. Government Accountability Office · December 22, 2015